DE2435867A1 - RADIATION POLYMERIZABLE COMPOSITION - Google Patents

Description

This invention relates to a radiation polymerizable composition and a method for polymerizing one such composition.

More recently, efforts have been made to find improved systems that are polymerizable by radiation have increased for various reasons, e.g. in the search for faster reacting systems, systems that lead to polymers lead with better properties and systems that are associated with low environmental problems. This is also there has been an increase in the commercial use of photopolymerizable systems.

In this area, however, there is still a need for new monomers and monomer-resin systems that have a low

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have odor, are toxicologically safe to use, and have little or no sensitivity compared to water. The known monomers, such as hydroxyethyl acrylate or hydroxypropyl acrylate, are because of their low radiation dose for the polymerization and because of the good strength and adhesion of the cured ones Coatings are useful, but the coatings made from these monomers are water sensitive, and besides, they are Monomers are toxic and can, for example, lead to permanent eye damage. Also have blends of these Monomers with other resins have unsatisfactory rheological properties, which makes handling and use difficult such mixtures is made more difficult.

This invention relates to a radiation-polymerizable composition which is characterized in that it is a monomer or a mixture of monomers of the formula

0 0

Il Il

R ₁ COR ₀ OCC = CH ₀ ^R 3

in which R- is an alkyl group with 1 to 5 carbon atoms, R _{0 is} an alkylene group with 2 to 6 carbon atoms and R_ is hydrogen or methyl, and either (a) a photoinitiator or (b) a polyethylenically unsaturated material or both (a) + (b), where (b) an unsaturated polyester resin or a compound having more than one pendant or terminal

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Is acrylyl or methacrylyl group.

The invention also encompasses a method of polymerizing such a composition by using this composition exposed to the action of a radiation source.

In the preferred monomers, R, CH-- and / or R ~ is -CH ₂ CH ₂ - or -CH ₂ CH (CH ₃ ) -.

The composition according to the invention can be polymerized by all forms of radiation, e.g. actinic light, if it contains a photoinitiator, or from accelerated electrons of high energy.

The compositions can be used for the production of .Formulierungen for coatings, printing inks, photoelectric Use resistors and flexible laminates.

The monomers contained in the composition according to the invention can be prepared in a simple manner by that a hydroxyalkyl acrylate or methacrylate with a monocarboxylic anhydride, such as acetic anhydride, or the converts corresponding halide.

To prepare the monomers, one can, for example, proceed in the following way:

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116 g (1 mol) of hydroxyethyl acrylate are placed in a 500 ml three-necked flask equipped with a stirrer, thermometer and reflux condenser. In the course of one hour, 112.2 g (1.1 mol) of acetic anhydride are slowly added, keeping the reaction temperature rises to 90 ⁰ C. The reaction is held at 90.degree. C. for an additional hour and then the temperature is held at 108.degree. C. for an additional 7 hours.

After the reaction, the contents of the flask are cooled, transferred to a separatory funnel and distilled three times Water washed. The product layer is essentially free of and not acetic acid or its anhydride converted hydroxyethyl acrylate. The product layer will stored over a molecular sieve to remove any residual To intercept water.

The 2-acetoxyethyl acrylate is obtained in one yield of 87% based on hydroxyethyl acrylate, the conversion being 98%. The product is a clear, pale yellow, water-white Liquid with a viscosity of 15 cp at 25 ° C.

Similarly, hydroxypropyl acrylate is converted to 2-acetoxypropyl acrylate in 85% yield with a 98 % conversion. The monomer is a clear, pale yellow - water-white liquid, with a viscosity of 18 cp at 25 ° C.

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When implemented on a large scale, acetic anhydride and hydroxyethyl acrylate are used in a similar manner Brought reaction. About 90% of the acetic acid and the excess anhydride are first removed by distillation, before washing the product with water. It is found by gas phase chromatography that there is a conversion of 98% has occurred. The analysis of the condensate shows a small loss of 2-acetoxyethyl acrylate,

Another suitable process for the preparation of 2-acetoxyethyl acrylate is the addition of a catalytic one Amount of cation exchange resin to the reaction vessel. After adding acetic anhydride the reaction is carried out for one hour and then the product obtained is isolated. The product is created in a yield of 75% with a conversion of 98%. Is preferred with a small excess of Acetic anhydride at a reaction temperature up to worked about 115 C. The reaction can be carried out under reduced atmospheric pressure or elevated pressure. Catalysts can be used if desired.

In addition to the aforementioned starting materials, the anhydrides of the can with similar results as anhydrides Propionic acid, butyric acid and like alkanecarboxylic acids can be used. Other suitable hydroxyalkyl acrylates or methacrylates are hydroxyethyl methacrylate, hydroxy

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propylraethacrylate, hydroxybutyl acrylate or methacrylate and like hydroxyalkyl acrylates and methacrylates. Instead of the anhydrides, the corresponding halides, such as acetyl chloride can be used.

The main advantages of these acyloxyalkyl acrylates or methacrylates include the low odor and low toxicity of these monomers. Others commonly used Monomers such as butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, are more volatile and / or have a stronger odor. Draw the monomers used in the invention consequently have the advantageous property that they have both a low odor and a low one Possess volatility.

Previously used monomers, such as the hydroxyalkyl acrylates and methacrylates, have a high polymerization sensitivity for stimulating the polymerization by radiation and a low volatility, but these monomers only give water-sensitive coatings. In addition, the monomers are toxic and difficult to handle. The monomers according to the invention significantly reduce the dangers both in terms of toxicity and handling. Skin and eye examinations were performed on "New Zealand" albino rabbits by standard methods, and for hydroxyethyl acrylate (HÄA) and 2-acetoxyethyl acrylate (AÄA) these results are given below.

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Undiluted HÄA leads to an irreversible loss of vision even after washing within 30 seconds. With AÄA there was a massive conjunctivite Hyperemia that began to subside after 24 hours. The washed eye showed no damage to the cornea or the inner eye. Mild iritis but no corneal damage was observed in the unwashed eye.

Inhalation of vapors at room temperature had no apparent effect with either monomer, but pathological examinations showed liver and kidney damage with HÄA and no damage with AÄA. In the case of inhalation studies at 100 C, a mortality of 100 % was observed with HAE, whereas ß-acetoxypropyl acrylate showed no damage at this temperature.

Both monomers caused moderate to severe burns to the skin so they should be handled with care. Skin absorption examinations showed an LD - " of about 0.1 g / kg in 25% solution for HÄA and an LDc ₀ of 0.5 g / kg in 40% corn oil for AÄA.

From these studies it can be seen that the invention a significant improvement in terms of the hazardousness of the radiation polymerizable material entry.

Another advantage of the compositions according to the invention can be seen in their viscosity behavior. Hydroxyalkyl

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Acrylates, such as hydroxyethyl acrylate, result in thixotropic and viscous filled compositions when combined with various types of unsaturated resins, this is likely due to the presence of a hydroxyl group. The rheology of such Systems is greatly improved by using the monomers according to the invention.

To improve the polymerization of the compositions according to the invention by actinic light, known photoinitiators can be added. Photoinitiators are compounds that are activated by actinic radiation so that they stimulate the addition polymerization of vinyl compounds. They are usually used in amounts of 0.01 to 5 % by weight based on the weight of the polymerizable material.

Numerous photo initiators are known. As examples be carbonyl compounds, polynuclear quinones, benzil, benzoin, substituted benzoins, benzoin ethers, azo and diazo compounds, organic sulfur compounds such as mercaptides, mercaptans or disulfides, peroxides and redox systems called.

Contains in addition to the acyloxy acrylate or methacrylate the compositions according to the invention comprise an unsaturated material with multiple ethylenic double bonds. Such materials are unsaturated polyester resins, terminally unsaturated vinyl ester resins, and others

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Acrylic resins with a variety of acrylate and methacrylate groups, all of these resins having more than one ethylene unsaturated group per molecule and these groups are polymerizable by the action of rays.

Unsaturated polyesters are well known and they are polymeric condensation products of polyvalent ones, usually Dihydric alcohols and polycarboxylic acids, usually dicarboxylic acids. Acid anhydrides are used for their production preferred if these are available. The unsaturated acids or anhydrides represent the ethylenic Double bond, which can be polymerized by initiators which form free radicals, are available. Typical unsaturated Acids are, for example, maleic, furaric, itaconic and citraconic acids or their anhydrides. Such unsaturated acids can partly be replaced by other acids such as amber, adipic, Sebacic, phthalic, tetrahydrophthalic, hexachloro-heptene-2,3-dicarboxylic acid or their anhydrides are replaced. Examples of suitable polyhydric alcohols are ethylene glycol, Called propylene glycol, diethylene glycol and 1,4-butanediol.

The term "unsaturated polyester" is used in its normal and usual meaning to include those above to designate the types of condensation polymers listed. Such condensation polymers are known.

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In another class of a polyethylenically unsaturated material which can be used in accordance with the invention it concerns substances that have more than one pendant or terminal acrylyl or methacrylyl group contain. Such materials are, for example, unsaturated esters such as di-, tri- and higher esters of acrylic acid or methacrylic acid with pentaerythritol and polypentaerythritol, similar di- and polyacrylic acid esters or methacrylic acid esters of aliphatic polyhydric alcohols such as ethylene glycol, triethylene glycol, polyethylene and polypropylene glycols, tr imethylolpropane, Glycerine, cyclohexanediol, mannitol or sorbitol.

The vinyl ester resins which can also be used as polyethylenically unsaturated materials are also well known and this term is used herein to encompass J resins made by the conversion of about equivalents Amounts of an unsaturated monooarboxylic acid can be obtained with a polyepoxide. Monocarboxylic acids that are considered here come, are for example acrylic, methacrylic, halogenated acrylic or methacrylic acid, cinnamic acid and Mixtures thereof and hydroxyalkyl acrylate or methacrylate half esters of dicarboxylic acids in which the hydroxyalkyl group Contains 2 to 6 carbon atoms. Although each used polyepoxide Glycidyl ethers are preferably polyvalent Phenols or polyhydric alcohols are used, whereby these substances also include the epoxynovolaks, which are usually a Have epoxy equivalent weights of about 150 and higher. The polyepoxides can be made from a halogen-substituted one, such as a bromine-substituted one , polyhydric phenol such as tetrabrorabisphenol A can be produced. One can as a result in a simple manner

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make a halogen-substituted vinyl ester resin.

The term "terminally unsaturated vinyl ester resins" also encompass those resins which, by reacting the · secondary hydroxyl group are formed. The hydroxyl group is formed when the epoxide reacts with the Acid and for modification it is with a compound that is able to react with a hydroxyl group, reacted, such as with an anhydride, an acid chloride or an isocyanate.

Other suitable polyethylenically unsaturated or polyethylenically unsaturated materials are acrylate capped polycaprolactone, polymeric resins with acrylate and methacrylate groups hanging on the chain, and twofold , or polyunsaturated materials obtained by reacting a di- or polyisocyanate with a hydroxyalkyl acrylate receives.

In the compositions according to the invention, the monomers can be mixed in any desired amounts with the unsaturated materials characterized above with several ethylenic double bonds. In general, the mixture contains about 30 to 60 wt.% Of the monomers and about 70 to about wt.% Of the ethylenically multi-unsaturated material. Customary additives, such as pigments, fillers and the like, may optionally also be present in the composition.

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The compositions according to the invention are useful for the production of coatings, printing inks, flexible laminates, laminates reinforced with glass fibers, photoelectric Resistance films and other suitable reprographs Materials that use radiation, such as actinic rays or ionizing rays of high energy, to polymerize the composition can be used. Under "radiation" or "rays" is used here any type of actinic or ionizing Radiation understood. UV lamps, radioactive materials, electron accelerators, like Van de Graaf - accelerator and the like. Equivalent radiation sources are well known to those skilled in the art.

The invention is illustrated in more detail by the following examples. All information about parts and percentages . are weight specifications, unless otherwise expressly stated is specified.

example 1

A solution of ß-acetoxypropyl acrylate (97%) and a Photoinitiator, d-butoxy-o ^ -pheny! Acetophenone (3%) was produced and applied to a steel sheet. The panel was placed under a series of 15,000 watt high pressure mercury UV lamps passed through. The solution was thereby with a curing speed of 12.2 m per minute in a hard solid converted.

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Example 2

A vinyl ester resin was made by reacting equivalent amounts of acrylic acid with a glycidyl polyether of bisphenol A with an epoxide equivalent weight of 186-192 in the presence of an amine catalyst and hydroquinone produced as a polymerization inhibitor. A part of it was diluted with 45% p-acetoxypropyl acrylate and it 3% of the photoinitiator from Example 1 were then added. The mixture was applied to a steel sheet and 0.05 seconds of a 15,000 watt high pressure mercury UV larape exposed. Of the. Film cured in air to a hard, tack-free coating that had no odor.

Example 3

Another vinyl ester resin was prepared by reacting a glycidyl polyether of bisphenol A having an epoxy equivalent weight of about 675 with an equivalent amount of acrylic acid as noted above. Part of the reaction product was diluted with 45% β-hydroxypropyl acrylate (HPA) and a second part with 45 % / 3-acetoxypropyl acrylate (APA). The viscosity of the first resin / monomer mixture was 9,500 cp, while the viscosity of the second mixture was 4,600 cp.

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Each of these resin / monomer mixtures was coated on a steel sheet to a thickness of 0.045 to 0.050 mm and cured in a nitrogen atmosphere using a 1 million electron accelerator at a dose of 6 megarads. In each case, a clear coating was obtained with a Knoop hardness between 9 and 11. In the case of crosshatched adhesion, the adhesion remained 100 % in both cases.

Both panels were immersed in boiling water for 3 hours, after which the following properties were found.

characteristic Resin / HPA Resin / APA colour dark brown clear as water liability completely ver
loren 100% received at
Cross hatching Bend over
mandrel Film fails without influence, 100%
liability surface small bubbles no bubbles, smooth Metal surface
area Rust stains through
Film surface Color unchanged,
no rust

Similar results were observed when the following vinyl ester resins were used in the above amounts with / 3-hydroxypropyl acrylate and mixed with p-acetoxypropyl acrylate:

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(a) The vinyl ester resin of Example 2.

(b) A half ester was prepared by adding equal molar amounts of hydroxyethyl acrylate and phthalic anhydride implemented. The half-ester obtained was then with an equivalent amount of a polyglycidyl ether of bisphenol A with an epoxy equivalent of 186-192.

(c) The same resin was used as in (b), except that the phthalic anhydride was used Dodeceny! Succinic anhydride was replaced.

(d) A 75/25 mixture of an epoxy novolak with a Epoxy equivalent weight of 175-182 and a polyglycidyl ether of bisphenol A with an epoxy equivalent weight of 192 was reacted with an equivalent amount of methacrylic acid.

Example 4

The vinyl ester resin of Example 3 was diluted with various monomers and similar in an electron beam Way hardened. In addition, the resin (b) of Example 3 was treated in the same way. The results obtained show the following table I.

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Table I.

Resin from monomers s example

Viscosity in cp. Tape adhesion with pencil crosshatching hardness

4 hours
boiling
water

2 months

Exterior

weather

tn
ο
co
co
ο

3 3

3.6

3.6
3.6

47% HPA

47% APA 47% BA

45% HPA

45% APA 45% AÄA

10

4 1

1

700 600% received

H

H
HB

H

H
H

strong strong bubbles yellowing education, encryption s chiechterung d. total Films

KE

KE

slight yellowing

strong blistering yellowing

KE KE
KE KE

KE - No effect ' HPA ' ■ Hydroxypropyl acrylate APA β 2-acetoxypropyl acrylate BA = n-butyl acrylate AÄA ^β acetoxyethyl acrylate

-P-CO

Example 5

Pigmented coatings were made from resins (b) and (c) of Example 3 by diluting the resins with various monomers and adding 50 %. Titanium dioxide pigment was added. The pigment was first incorporated in a high shear mixer and then ball milled for 24 hours. Films 0.05 mm thick were cast on a substrate and cured with an electron beam, as already explained. The results are shown in Table II.

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Table II

Resin from
example Monomer viscosity
in ep Tape adhesion
Cross hatching pencil
hardness 4 hours
boiling
water I. 3, b 40% HPA 1 900 100 2 H some ver
yellowing I- ¹
oo cn 3, b 50% APA 1 100 90 2 H KE I. CD
CD 3, b 50 % AÄA 980 90 2 H KE 8 O 7 y 3, c 45 % HPA 600 100 1 H. strong ver
yellowing 3, c 45 % APA 450 100 1 H. KE 3, c 45% AÄA 400 100 1 H. KE

Example 6

The vinyl ester resin of Example 3 and resin (b) were made with either hydroxypropyl acrylate (HPA) or acet: oxypropyl acrylate (APA) or mixtures thereof. There were pigmented coating compounds containing 43% TiO_, and the rheological properties of such compositions were investigated. By adding APA reduced the undesirable thixotropic properties of the formulations. It refers to an improvement especially for the ablation of the Coating with the roller is important. The decrease in the thixotropic index enables a more even flow distribution after the pressure of the applicator has been removed. the improved flow properties can be seen from Table III.

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Table III

cn CD CD OO CD -J

CD

Resin from
example Z HPA % APA 4th viscosity
5 RPM 50 RPM 400 Thixotropic
Index ** 3 80 OB M 2 720 3 950 1.8 3 60 - 1 200 2 240 1.06 3 35 25th 1 300 1,390 1.03 3 - 60 1 340 920 0.96 3b) 65 500 1 100 1.63 3b) 60 Wed M 600 335 1.45 3b) 22nd 38 340 940 1.01 3b) - 50 900 0.96

No. 3RVT Brookfield

Ratio of viscosity at 5 RPM / 50 RPM

ro

ro 4> co

cn

CXD CD

Claims (9)

Patent claims in which R _{1 is} an alkyl group of 1 to 5 carbon atoms, R _{2 is} an alkylene group of 2 to 6 carbon atoms, and R ~ is hydrogen or methyl, and either (a) a photoinitiator or (b) a polyethylenically unsaturated material, or both Contains (a) + (b), where (b) is an unsaturated polyester resin or a compound having more than one acrylyl or methacrylyl group pendant or terminal. 2. Composition according to claim 1, characterized in that R _{1 is} CH ₀ -. Lo 3. Composition according to claim 1 or 2, characterized in that R ₂ -CH ₂ CH ₂ - or -CH ₀ CH- Z ι Is CH _3. 5 Ü JB υ / / 1 0 k 9 4. Composition according to any one of claims 1 to 3, characterized in that it also contains a pigment or a dye. 5. Composition according to any one of claims 1 to 4, characterized in that the polyethylenically unsaturated material is a terminally ethylenically unsaturated vinyl ester resin is. 6. A composition according to any one of claims 1 to 5, characterized in that it comprises a mixture containing from 30 to 60 wt.% Of monomer and 70 to 40 wt.% Of a terminally unsaturated Vinylesterharzes, based on the combined weight of the monomer and the resin . 7. Composition according to any one of claims 1 to 6, characterized in that they 0.01 to 5 wt.% Of a photoinitiator, based on the weight of the polymerizable present Materials, contains. 8. A method for polymerizing the compositions according to any one of claims 1 to 7, characterized I show net that one α ie the action exposed to a radiation source. 9. The method according to claim 8, characterized in that the composition contains a photoinitiator and the radiation source used is the actinic Emits radiation. 509807/10 49